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Phased Work Plan Developed
to Move Cape Hatteras Lighthouse
International Chimney Corporation has presented the National Park Service a phased work plan for the move of the Cape Hatteras Light Station. The relocation of the historic Cape Hatteras Lighthouse will be divided into seven (7) phases of work: preparatory work; foundation removals and temporary support; structure load and transfer lifting; structure relocation; structure lowering and load transfer to foundation; emergency procedures for structure and system preparation, and if necessary, a 7th phase of temporary storage in route.
"This approach provides an orderly and logical schedule to this project," said Bob Reynolds, General Superintendent of the National Park Service's Outer Banks Group which includes Cape Hatteras National Seashore. "Requirements for the installation and monitoring of instrumentation on the lighthouse will be identified under a separate plan."
The preparatory work phase includes the identification and installation of bracing, reinforcing, or structural enhancement necessary to prepare all the structures for the relocation process. The Principle and Double Keepers Quarters, and the Oil House will be moved as well as the lighthouse. Following an authorized outage of the light by the US Coast Guard, all electrical service will be terminated to the beacon and lens protection and bracing will be put in place. Brickwork inspection, necessary splinting, exterior plinth reinforcement, entry stairway removal and entryway bracing are part of the preparation necessary before the lighthouse can be moved.
The next step, foundation removal and temporary support, calls for cutting and coring operations which will selectively remove portions of the existing foundation in order to insert the steel support frame. Additionally, adequate temporary support, including shoring, bracing, etc. under the structure will be utilized prior to transferring the lighthouse load to the support frame. Excavation and dewatering will be part of this phase. A 3/8" heavy duty diamond cable wire saw will be used to form the plane of separation. The stone below will be removed and as soon as the existing wooden foundation mat is exposed, shoring towers will be installed and the main and cross steel beams will be put in place.
During the structure load transfer and lifting phase, the lighthouse will gradually be transferred from the temporary support to the support steel frame. A unified hydraulics system (all lifting points raise at the same rate) will lift the lighthouse off its foundation and relocation equipment will be installed underneath. The same system will be used to lift and transfer the other light station structures as well. It is anticipated that the Principle and Double Keepers Quarters, and the Oil House will be moved before the lighthouse.
In the relocation phase the lighthouse will travel on steel rails or tracks to its new site. A "I" beam matting will be laid over improved soils to the edge of the excavation and the track placed under the lighthouse and the already installed main beams and roller dollies. Push jacks will then be installed between the track steel and the main beams. The push jacks will be activated in unified hydraulics and at the end of each 5-foot stroke, the jacks are to be retracted, the system re-charged, and readied for the next 5-foot stroke. As the lighthouse is moved towards its new site, it will be gradually raised to existing ground level, a rise of about 6 inches in 100 feet. Only a third of the travel system will be laid at any one time; as the transportation system and the lighthouse move past a point, the part of the system already used will be retrieved and leap-frogged ahead and put in place. The double keeper's quarters and primary keeper's quarters will be transported via rubber tired dollies to their new location. The oil house, cisterns and granite fence footer shall all be transported via flat bed trailer.
"Common to the relocation phase for the lighthouse, double keeper's quarters, and primary keeper's quarters is the concept of cushioning the structure on hydraulics rigged in common pressure on three zones," explained Mr. Rick Lohr, President of International Chimney Corporation. "Since three points determine a plane, any inconsistency which might develop along the move route, and which might cause the lighthouse to raise or drop, would be offset by the three zone operation allowing for the compensation of pressures between hydraulic zones instead of transmitting stress to the structure. This hydraulics system will keep the structure in a uniform plane and accommodate any inconsistencies. In essence, the move system allows for the compensation necessary to travel over uneven ground."
Last, once the lighthouse has arrived at its new site, the structure will be lowered and its weight transferred to the new foundation. The process is essentially the reverse of the procedure used to lift the lighthouse. The new foundation mat will be installed at roughly the same relative elevations at the lighthouse's original wooden mat, but will be constructed of reinforced concrete approximately five feet thick. Plinth salvaged from the original site will be re-installed individually in their original matched marked position. The Lighthouse and associated buildings will be set to their proper elevations, and providing an adequate support for the structure until the foundation can be built underneath.
"An emergency procedure phase which identifies the needs that will be implemented on the lighthouse and the move system should unexpected inclement weather threaten the project has been developed as well," said Superintendent Reynolds. "We have planned this effort when the risk of severe weather is at its least, and our hope is that our effort in this phase will be limited to the planning."
If necessary a temporary storage in route phase will affect only the double keeper's quarter, primary keeper's quarters, oil house and cisterns. All cisterns have to be removed before the double keeper's quarters and primary keeper's quarters can be moved, and re-set after the keeper's quarters are re-located. The oil house, while not initially in the way, must be moved out of the way before the lighthouse.
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